1. Field of the Invention
This invention relates broadly to medico-surgical tube devices (MSTD). More particularly, it concerns thoracic catheters, i.e., MSTD that are designed for postsurgical drainage purposes to remove fluids or other matter from the chest or other body cavities of patients.
2. Description of the Prior Art
Thoracic catheters are also variously referred to by surgeons and other persons that work with them as postsurgical drainage tubes and intercostal catheters. By whatever name they may be called, this class of MSTD are positioned in a patient at the completion of a surgical procedure to remove body fluids that are invariably generated by the patient's body as a consequence of the surgery. This invention may be utilized generally with this class of MSTD.
The use of the primary incision created by the surgical procedure on the patient as an exit for thoracic catheters is usually avoided to safeguard against contamination of the body cavity from which fluid is to be withdrawn by the catheter. Instead, the surgeon determines a suitable site other than the primary incision and makes a short secondary incision for catheter withdrawal. The proximal end of the catheter is then inserted through the primary incision and threaded toward the secondary incision. The surgeon then inserts an instrument, such as a Kelly clamp, from the outside of the patient into the secondary incision and grasps the proximal end of the catheter with the clamp to draw it through the secondary incision leaving the distal end properly located in the patient's body. Hence, this type of implantation of a catheter is opposite to the more conventional method in which the distal end of a catheter first enters the patient's body.
It has been recognized by catheter designers that the leading proximal end (sometimes called machine end) of thoracic catheters and the procedure needed to effect their implantation should cause minimal damage to tissue at the secondary incision site. One catheter design for this purpose has the proximal end cut with a long taper (see U.S. Pat. Nos. 3,190,290 and 3,295,527). This helps in withdrawing the catheter by permitting firm grasp of the end with a clamp, but the taper cut leaves raw cut edges that can damage tissue.
Another design uses a closed end nose having a nipple-like tip on the proximal end of the thoracic catheters (see U.S. Pat. No. 3,589,368). While this design mitigates tissue damage, the nipple tip is grasped on the outside by the jaws of the Kelly or like clamp. Hence, the overall width of both jaws with the nose tip between them is substantially increased and the grasping of the nose in this design with the clamp is not as positive as in the tapered cut design.